--- title: Classification of BGP Route Leaks (RFC 7908) «... description: A walkthrough of RFC 7908's taxonomy of BGP route leaks, covering six distinct leak types: hairpin turns (customer propagating routes between two ISPs),... canonical: https://daily.dev/posts/classification-of-bgp-route-leaks-rfc-7908-ipspace-net-blog-pkb3mv7gc twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Classification of BGP Route Leaks (RFC 7908) « ipSpace.net blog | daily.dev og:description: A walkthrough of RFC 7908's taxonomy of BGP route leaks, covering six distinct leak types: hairpin turns (customer propagating routes between two ISPs),... og:url: https://daily.dev/posts/classification-of-bgp-route-leaks-rfc-7908-ipspace-net-blog-pkb3mv7gc og:image: https://api.daily.dev/og/posts/pkB3MV7gc.png og:image:alt: Classification of BGP Route Leaks (RFC 7908) « ipSpace.net blog og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Classification of BGP Route Leaks (RFC 7908) « ipSpace.net blog **[ipSpace.net Blog](https://daily.dev/sources/ipspace)** · 4 min read · 0 upvotes · 0 comments ## Summary A walkthrough of RFC 7908's taxonomy of BGP route leaks, covering six distinct leak types: hairpin turns (customer propagating routes between two ISPs), lateral leaks (peer routes forwarded to other peers), peer-transit leaks (peer routes leaked to upstream transit), prefix re-origination (advertising third-party prefixes as one's own), prefix deaggregation leaks (BGP optimizers advertising more-specific prefixes), and accidental leaks of internal or more-specific prefixes from IGP-to-BGP redistribution. Each type is explained with real-world consequences including traffic congestion, unexpected transit costs, and internet disruptions. The post also notes a real-world example involving a BGP optimizer with insecure defaults that caused widespread internet outages. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What are the different types of BGP route leaks defined in RFC 7908? RFC 7908 defines six BGP route leak types: hairpin turn (customer propagates routes between two ISPs), lateral leak (ISP forwards peer routes to another peer), peer-transit leak (peer routes leaked to upstream transit), prefix re-origination (advertising third-party prefixes as one's own), prefix deaggregation leak (BGP optimizer advertises more-specific prefixes with unmodified AS-path), and accidental leak of internal or more-specific prefixes from IGP-to-BGP redistribution. _Network engineers dealing with BGP misconfigurations track incidents and advisories like these on daily.dev._ ### What causes a BGP hairpin turn route leak and why is it dangerous? A hairpin turn occurs when a customer AS lacks output filters and propagates routes received from one upstream ISP to another. It is dangerous because the path through the customer AS may appear as the shortest AS path, and many ISPs prefer customer routes over peer routes regardless of AS path length — a behavior documented as BGP wedgies in RFC 4264 — causing unintended traffic flows through an underpowered link. _Engineers hardening BGP policy configurations find relevant routing security discussions on daily.dev._ ## Similar posts on daily.dev - [Routing Information in Iran](https://daily.dev/posts/routing-information-in-iran-hvu0wyakw) · Hacker News · 0 upvotes · 0 comments - [A closer look at a BGP anomaly in Venezuela](https://daily.dev/posts/a-closer-look-at-a-bgp-anomaly-in-venezuela-wjsdlj7zk) · Cloudflare · 1 upvotes · 0 comments - [Telecom Attack Surface: SS7, BGP & Nation-State Intrusions](https://daily.dev/posts/telecom-attack-surface-ss7-bgp-nation-state-intrusions-v1wejqstm) · Cyble · 0 upvotes · 0 comments - [Route leak incident on January 22, 2026](https://daily.dev/posts/route-leak-incident-on-january-22-2026-fllzay8ed) · Cloudflare · 1 upvotes · 0 comments - [The Never-Ending IPv6 Loopback Prefix Saga « ipSpace.net blog](https://daily.dev/posts/the-never-ending-ipv6-loopback-prefix-saga-ipspace-net-blog-4nlhgh10l) · ipSpace.net Blog · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security), [#bgp](https://daily.dev/tags/bgp) [View this post on daily.dev](https://daily.dev/posts/classification-of-bgp-route-leaks-rfc-7908-ipspace-net-blog-pkb3mv7gc) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Classification of BGP Route Leaks (RFC 7908) « ipSpace.net blog","url":"https://daily.dev/posts/classification-of-bgp-route-leaks-rfc-7908-ipspace-net-blog-pkb3mv7gc","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/classification-of-bgp-route-leaks-rfc-7908-ipspace-net-blog-pkb3mv7gc"},"datePublished":"2026-08-11T08:56:03.251Z","dateModified":"2026-08-11T09:28:27.990Z","description":"A walkthrough of RFC 7908's taxonomy of BGP route leaks, covering six distinct leak types: hairpin turns (customer propagating routes between two ISPs),...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/c79bddb82af3545418b98fc95ba9e97c?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/c79bddb82af3545418b98fc95ba9e97c?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"ipSpace.net Blog","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"ipSpace.net Blog","logo":"https://media.daily.dev/image/upload/s--xS7E82MT--/f_auto,q_auto/v1786438303/logos/ipspace?_a=BAMAMicg0","url":"https://daily.dev/sources/ipspace"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/classification-of-bgp-route-leaks-rfc-7908-ipspace-net-blog-pkb3mv7gc","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"security,bgp","timeRequired":"PT4M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"ipSpace.net Blog","item":"https://daily.dev/sources/ipspace"},{"@type":"ListItem","position":3,"name":"Classification of BGP Route Leaks (RFC 7908) « ipSpace.net blog"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/classification-of-bgp-route-leaks-rfc-7908-ipspace-net-blog-pkb3mv7gc#faq","mainEntity":[{"@type":"Question","name":"What are the different types of BGP route leaks defined in RFC 7908?","acceptedAnswer":{"@type":"Answer","text":"RFC 7908 defines six BGP route leak types: hairpin turn (customer propagates routes between two ISPs), lateral leak (ISP forwards peer routes to another peer), peer-transit leak (peer routes leaked to upstream transit), prefix re-origination (advertising third-party prefixes as one's own), prefix deaggregation leak (BGP optimizer advertises more-specific prefixes with unmodified AS-path), and accidental leak of internal or more-specific prefixes from IGP-to-BGP redistribution. 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